The invention relates more especially to the field of audio and/or video digital reception systems complying with the DVB standard (the acronym standing for “Digital Video Broadcast”).
The DVB standard is based on the audio and video MPEG-2 standard (the acronym standing for “Motion Picture Expert Group”) and relates more especially to the transmission of MPEG-2 signals by satellite, by cable or by a terrestrial route.
The transponders used may be of the MCPC type (the acronym standing for “Multiple Channel Per Carrier”) or of the SCPC type (the acronym standing for “Single Channel Per Carrier”).
Transmission in MCPC mode allows the broadcasting of several audio and/or video channels on a single frequency by occupying the whole bandwidth of a transponder. In a transmission in SCPC mode, each programme uses a distinct frequency, the transponder being able to contain several frequencies.
The programme broadcasters can use various transponders to build their bouquet of programmes. Specifically, for cost reasons, certain broadcasters who do not have their own network, hire or purchase portions of frequency bands in order to build their bouquet of programmes. Certain programme bouquets therefore contain SCPC transponders and also MCPC transponders. For example, in the case of satellite reception, the band available thereon may be shared by several customers.
Various types of installation of programme bouquets exist. The installation which is simplest for a user is the blind scanning installation. This type of installation allows the user to disregard the signalling parameters which are necessary relative to more sophisticated installation processes. The time to install, under blind scanning, a bouquet on a reception apparatus, such as a set top box or a digital television, is inversely proportional to the sought-after data rate. In the case of the MCPC mode the data rates are of the order of from 15 to 40 Mbaud (mega baud) per second. The data rates in SCPC mode run between 2 and 15 Mbaud per second.
This explains why if an identical installation procedure is used, the time required for installation will be larger under SCPC than under MCPC.
The installation of a bouquet using MCPC and also SCPC transponders under blind scanning is very lengthy since it is necessary to traverse the entire frequency band using a frequency increment which corresponds to the capture span of the components effecting this installation. The latter being calculated on the basis of the smallest symbol data rate sought therefore corresponds within the framework of a mixed multiplex to an SCPC symbol data rate.
The installation of the various programme bouquets using SCPC and also MCPC transponders is therefore much more lengthy than the installation of programme bouquets comprising MCPC transponders only.
The invention therefore proposes to reduce the installation time for programme bouquets using SCPC and MCPC transponders.